In 1964, Barry Goldwater was the Republican nominee, running against Lyndon Johnson. Goldwater was from what was then the furthest acceptable edge of the right wing. He was so effectively presented as an extremist that famously in his nomination acceptance speech he responded, “I would remind you that extremism in the defense of liberty is no vice! And let me remind you also that moderation in the pursuit of justice is no virtue!”

In one of the most famous political ads of all time, LBJ successfully painted him as too irresponsible to trust with nuclear weapons:

Nate Silver now has dug up another ad from that campaign: “Confessions of a Republican” voting for LBJ. Silver calls it “strange and kind of amazing.” I’d add “mesmerizing.”